Beach flowers

A little group of friends strolled out to the ‘island’ at the mouth of Fish Creek. On the berm along the way, we found swathes of pink shooting stars, showy yellow buttercups, and blue lupines—a carpet of color. Out at Cowee Meadows this month, we’ll make an annual pilgrimage to enjoy the fields of wild iris, dotted with chocolate lilies and other flowers, and the banks of wild rose. These flamboyant favorites get most of our attention and appreciation.

It occurred to me, however, that there is an unsung gallery of flowers on beaches and intertidal meadows. These flowers are generally smaller and less showy, but surely they would have some interesting stories to tell. So I did a bit of digging and found surprisingly little detailed information about their life history. In some cases there were contradictory reports, which might mean either that certain reports are simply wrong or that the habits of a species vary from place to place. The bottom line is that there’s plenty of room for some detailed study of pollination, seed dispersal and germination, survivorship and longevity, and all the facets of life history.

In the meantime, here are a few gleanings about some of the seaside flowers—with all the above caveats plus the confusions of alternative scientific and multiple common names (too many to list, in some cases). Most of these species are widespread perennials in the northern hemisphere.

–Sea milkwort (Glaux maritima or Lysimachia maritima): Small, white flowers, pinkish at the base, grow from the junctions of leaves and stem. There are no true petals; the flower is formed of sepals that have taken on the role of advertising for pollinators, presumably small insects, although the flowers might be self-fertile. This species can also reproduce vegetatively, from buds on rhizomes (underground stems). It’s very salt-tolerant; salt glands on leaf surfaces excrete excess salt and the leaves can store fresh water. Milkwort reportedly makes mycorrhizal connections to the roots of other plants. Common on our beaches and other coasts, it also grows in saline habitats in the interior.

Honckenya peploides

–Sea sandwort or seaside sandplant or (locally) beach greens (Honckenya peploides): Clumps of this plant dot upper sandy beaches. Its branches spread over the ground and most reports indicate that it can spread vegetatively, by rhizomes. The flowers have nectar and are said to be honey-scented and pollinated by a variety of insects; I saw several kinds of small flies on the flowers. Some of the flowers have very small white petals, no male parts, and are strictly female. Others have white petals about as long as the sepals; these are hermaphroditic, having both male and female parts. Many of the reports that I read confusingly called these simply ‘male’, but they are self-fertile to some degree, perhaps setting fewer seeds than the fully female flowers.  Females reportedly grow more slowly than hermaphrodites. I recently searched some of our beaches for examples and found three clumps with wide-open female flowers on all the stems and several all-hermaphrodite clumps. I was fascinated to read that clumps with many flowering stems may be comprised of several genotypes but somehow all have the same sex-expression; this needs some elucidation.

–Oysterleaf or oysterplant (Mertensia maritima): Rather showy flowers are pink at first, turning blue; we’ve also seen rare individuals with white flowers. Although they are sometimes visited by insects, they are said to be mostly self-pollinating. The stems spread out on the surface, originating from a big taproot. The fruit is a ‘nutlet’ that can float in sea water for two weeks or more, and the seeds can be dormant for several years.

–beach pea (Lathyrus japonicus): The flower is usually pink or red at first, turning blue-purple at maturity; occasionally, all-white flowers are produced. The flowers absorb UV and nectar guides then become visible. It’s a complex flower that has a lower keel surrounding the sex organs and two spreading wings that are generally paler than the rest of the flower. It’s pollinated by bees, and I expect that (as happens with lupine) the bees have to pry open the flower to do the job. Pollen is shed into the keel and stays viable until the stigma becomes receptive. The seeds float and are viable in saltwater, although the plant can also spread by rhizomes. Bruchid beetles often bore through the hard seed coat, breaking dormancy, which would enhance the germination rate unless the beetle larvae eat too much; wasp parasites that kill the larvae reduce damage and allow good germination. Beach pea (like lupine and other legumes) has root nodules containing Rhizobium bacteria that fix atmospheric nitrogen into a form usable by plants.

–Beach lovage (Ligusticum scoticum): The small, white or pinkish flowers in a cluster on top of the plant can be pollinated by flies and other generalist flower-visiting insects. The plant is tolerant of salt spray. We have observed that bears commonly dig up and eat the root, but the possible effect of this activity on the lovage population is not known. One report suggests that perhaps it can regenerate from root fragments.

–Glasswort or pickle weed or sea asparagus (Salicornia virginica): Hermaphrodite flowers are tiny, in groups of three, sunk in hollows at the stem joints on a spike. They may self-pollinate. This plant is considered to be a perennial but may be annual in some places. In California, it responds to the addition of nitrogen and phosphorous even in estuaries with high nutrient levels. It provides essential habitat near San Francisco for the endangered salt-marsh harvest mouse.

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On tanagers and silverweed

My home pond has been rather quiet lately. Two or three unemployed male mallards loaf around companionably while their females are egg-sitting. Sometimes just one male is there, a female (a late-nester or re-nester) visits briefly, and they forage side by side. But if she comes when two or three males are there already, all companionability disappears and there are serious battles between males. On a sunny (!) day after many days of rain, little fish were rising to the surface; a roving kingfisher swooped down to take one away. Up in the trees, the big treat was seeing a juvenile junco and a juvenile nuthatch, well-feathered, flying, fully competent, but each one still being fed by an attending parent. And out my kitchen window, I saw two really tiny squirrels, frisking about on the tree trunks.

A lucky friend stepped out of her door one day and saw an unusually colorful bird—a male western tanager. The fairly gaudy yellow and black body is topped by a head that’s red or red-orange. I haven’t done a proper analysis but it seems to me that we have fewer really colorful birds than does the eastern deciduous forest, with its grosbeaks, orioles, cardinals, and (yes) tanagers. Western tanagers are not common here. Years ago, my field crew and I were thrilled to find a nest in a thicket at the head of one of the small bays on the west side of Glacier Bay (if I recall correctly).

Photo by Kerry Howard

We live near the northern limit of the western tanager range. They nest all over the mountain west and winter in Mexico and Central America, feeding on insects and fruit. On the nesting ground, they are territorial; both male and female chase away intruders. First-year males can breed but are subordinate to older males, so they don’t get first choices of where to set up a territory. Pairs are socially monogamous; extra-pair activity is little studied. Females build their cup-shaped nests (twiggy on the outside, lined with grass, hair, rootlets, etc.) often on a conifer branch but sometimes in deciduous trees. Males accompany their mates during nest-building and egg-laying, presumably as a guard against possible philanderers. A clutch of three to five eggs is incubated for almost two weeks by the female, who may sometimes be fed by the male. Chicks stay in the nest about eleven days, fed by both parents. Very young chicks are fed mashed up bugs regurgitated by the mother, while the male apparently brings in small whole insects; older chicks get bigger insects. There is usually just one brood per season.

The red, orange, and yellow colors come from carotenoid pigments. This tanager makes its red plumage pigment directly, probably from insects in the diet, in contrast to other North American tanagers, which make their red plumage by converting yellow pigments that are also derived from their food. The intensity of the red on the head varies, perhaps as a result of differences in insects eaten. It is apparently not known if females choose their males in part on the basis of coloration. Many other studies of western tanager life history are reported to be under way, so stay tuned.

Out on the upper tide flats, we commonly see a plant called silverweed. The common name derives from the silky white hairs that cover the underside of the leaves. I found no information on possible functions of those hairs, although it seems possible that they might retard evaporative water loss by protecting the leaf surface. Be that as it may, silvery leaves upturned by the wind made a field of pink shooting stars even more spectacular.

Silverweed flowers are yellow; they may or may not be self-fertile (depending on what source you read). The flower has nectar and is visited by bees, flies, and beetles. It also has stolons or runners that spread out over the ground, and new plants can grow from nodes on the runners.

The Latin name for silverweed is either Potentilla anserina or Argentina anserina—the proper genus is debated. My interest was caught by the diverse explanations for the long-standing species name ‘anserina’. ‘Anser’ means goose in Latin. One suggested reason for relating the plant to geese that the leaves may have reminded someone of a goose’s foot marks. This strikes me as ludicrous, because I see no resemblance whatsoever. Another explanation is that by growing in rock crevices, the plant is safe from grazing geese (graylag geese in Europe). This notion wouldn’t apply here, because the plant grows mainly on flat sediments that offer no protection from geese. The third explanation is that the plant was used (in Europe) to feed geese. This is getting closer to something real—on our upper intertidal meadows, Canada geese regularly dig up and eat the roots. So we find small pits scattered over the flats where goose bills have grubbed up the roots. One final note: near the mouth of Fish Creek, a group of strolling friends found several spots where the ground was littered with dozens of fresh, bright green spruce tips. We had no good way to account for that–a natural phenomenon, maybe wind, or just kid stuff?